Laser Removes Rust Like Magic

If you’ve worked with steel or iron, you will be very familiar with rust. You will have an impressive armoury of wire brushes and chemicals to deal with it, and your sandblasting guy is probably in your speed-dial list.

We’ve had more than one Hackaday reader contact us of late with videos showing an apparently miraculous handheld laser unit effortlessly stripping away rust, and leaving a near-perfect surface with little mess. Can it be real, they ask, is it an internet hoax? After all if you have done battle with the dreaded iron oxide you’ll know there is no miracle fix to the problem, however you deal with it there has traditionally been hard work involved.

So after a bit of research, we find CleanLaser, the German company whose products feature in the videos. Quoting their website: “Powerful, very short, rapid and moving laser pulses produce micro-plasma bursts, shockwaves and thermal pressure resulting in sublimation and ejection of the target material”. So yes, it seems they’re real.

The website is at pains to stress the environmental benefits of the devices over comparable sandblasting or similar technologies, but has very little information on their safety. They are available in power ratings from 12W to 1KW which is a hell of a lot of laser power to be projecting, yet the operators seem only to be wearing goggles. Perhaps this comes back to the “Powerful, very short, rapid and moving” bit in the quote above, is there no point source to sear your retina? Laser experts please enlighten us in the comments.

If you work with metal or grew up in a metalworking business, this machine probably has you salivating. Sadly for hackers and makers though it’s probable that it and ones like it will be out of our price range for quite some time. Still, the prospect of a guy with one in an industrial unit appearing in most towns can’t be too far away, and that can only be a good thing

The video shows the machine in action. Rusty fire-grate in, perfect shiny surface out. Perhaps only those of you who have spent many hours with a wire brush will understand.

It’s quite impressive people are doubting this even exists, even people who know quite a bit about technology. Goes to show what an advance it is. If it can make cars fly, I’ll be ready to admit the year 2000 has arrived.

Let me be the very first to call BS on this. I really expect to see a Kickstarter link on their site somewhere, but it’s nowhere to be seen. Just not believing that that nice clean smooth surface was under that much rust. At the very least, there should be evidence of pitting from the corrosion. And when the operator in the video did a little test swath before attacking the “rust”, the light wasn’t very bright, and it made the same noise as it did when actively removing coating.

That doesn’t even look like iron. My guess: it’s a zinc or aluminum alloy casting which has been coated with something ablative that just happens to look like rust. They never SAY in the video that it’s rusty iron; we’re just left to assume that.

So you think this is an incremental scam…we’ve seen plenty of laser cleaning videos that look just as miraculous, laser cleaners are definitely a fact. But you’re proposing that this is just a normal laser cleaning operation, and the “rust” isn’t rust. I suppose that’s a valid suspicion.

However, I come down on the side that this is real. I’ve seen enough electro rust removal to not be very surprised at the amount of detail still present under the rust. The video doesn’t zoom in enough to show any pitting damage, so you can’t really say it’s not there. I find that a lot of the detail loss during rust removal is due to the aggressive physical methods normally required to remove the rust.

Dude, calm down. The rust on that part is known as flash rust. It will happen if you leave a brand new cast iron part outside in a marine environment, overnight. The layer of rust was very thin and the part did not have any damage because it was simply flash rust. On something like a rusty engine that’s been in water for 20 years, it would certainly take a lot more work to clean it, and the laser wouldn’t remove the chunky rust, just the oxides on the surface. As soon as the surface become “shiny” it stops working, because there is more reflected light than absorbed.

I agree that current tech could do this to rust, but the lack of safety measures for such powerful lasers seems suspect, or is there some magical safety built in that doesn’t fire the laser at reflective material?

I picked up this article because I have something of a specialist knowledge in this field. My dad is getting on a bit now, but he’s still a blacksmith as he has been all his life and mine, and his workshop and forge are still next to our house as they always have been. I’ve thus seen a lot of rust in my time, and a lot of different surface treatments to deal with it.

I can’t vouch for the video ‘cos I didn’t make it. But I can observe what I see, and that’s cast iron, not steel. (You’d be very lucky to see any wrought iron these days outside heritage work)

Cast iron can pit just like steel, but it’s a lot more resistant. And depending on the surface treatment it can come up very smooth after rust removal. I’ve seen just that kind of finish come up on cast-iron fire furniture after sandblasting, indeed my dad has a fireplace on which he’s kept that finish, he waxed it after the blasting. So yes, that looks like iron to me, and that finish doesn’t look out of the way.

I would be surprised if the laser is visible light, what we’re seeing is its effect on whatever is on the surface. So the test swath won’t be very bright, it’s on a largely clean workbench rather than a rusty grate.

The manufacturers have a worldwide list of distributors and operators. Real metal preparation companies in real business, doing real work. If it was BS they wouldn’t have that, instead you’d see a vapourware crowdfunding campaign and little evidence of guys in workshops actually stripping rust.

The company says it is a “J H Norton” company which is an abrasive maker. The wierd thing is that there doesn’t appear to be any debris or fumes so where is the rust going? I would have expected at least fumes if the rust is being burned off. There is also a video of paint removal also with no apparent debris or fumes and which doesnt seem to remove bare metal. On the face of it, it doesn’t make sense. Maybe it is a hoax.

You can apparently buy or rent these, it would be a bit pointless to set up a whole company just for a bit of video-shoppery. Maybe you can’t see the debris, the laser light blinding the camera, or maybe the fumes aren’t very thick. I doubt it’s a hoax. A website tells me the debris is turned to plasma, so perhaps the iron falls away as tiny particles, and the oxygen joins the air. Or perhaps it re-forms iron oxide in tiny particles.

High-power laser zapping is used in other fields. Producing powerful bursts for very short periods of time means average power isn’t too high, so you wouldn’t need a huge laser if your periods are short enough. Probably the short period actually helps, producing a stuttering effect that helps blast away debris, rather than a constant heating.

The company exists since ´97 and has 90 co-workers. It won prizes and even some officials (Turkey president) tried it. So the idea it is a scam is not far-fetched but plain irrational, maybe knowing it is not US-made biased your opinion and made you doubt about it.
About the dust and dirt generated, it is apparently vacuumed by the apparatus.
the laser is very likely Q-switched also.

That hose isn’t just a vacuum, it is also the optics that carries the light from the laser to the laser “head” that he is holding. If you check out the website, you will see the laser itself is a huge cart, similar to medical YAG lasers, and the operator holds the “head” in his hand.

People who think this is a scam need to do a little research to realize this is legit.

This thing is a YAG laser.. Its is very real, and YAG lasers can do some amazing things. The pulse energy is very high, especially if it is Q-Switched, and the wavelength cannot pass through your cornea, hence the glasses. This does not mean the laser cant hurt you, it wont pass through your cornea, but simply burn it to oblivion.

The actual process is called Laser ablation, which is a process that occurs at high power concentrations, and basically rips the molecules apart into their constituent components. Even small YAG lasers like an SSY-1, when focused to a tiny spot, can cause auto-ignition of air because of the power density.

YAG lasers are used for all kinds of industrial and medical operations. They weld very thick Ship Hull steel plates with them, and numerous other industrial material processing with them all the time. They are used for dental work, skin work, and other kinds of surgery as well.

What I wonder about is how such power densities are achieved for arbitrary depths (focus depth), and especially along a line instead of a single dot… what frequency is the laser firing at? it sounds audible assuming no aliasing is taking place. Where and how exactly is the sound generated? in the device itself, or photoaccoustic effect? how is a striped pattern prevented when moving the switched laser beam across the surface? I have no clue if this is real or fake, but I do note that if fake it could be very easy to fake, as the bright line can tell the video effect where on the object the beam has already “cleaned”, except there is a piece of rust shadowed by a piece of metal on the first side treated…

The laser is pulsed at an adjustable rate of 15KHz to 40KHz. The spot size (beam waist) is 2mm at the focal distance of 10cm. The Rayleigh range allows a useful working distance of ~3cm. The focal distance is factory adjustable. The pulses are scanned across the surface in a line at a speed that allows approximately 5000 pulses to form a line. It does not form a streaked pattern because the laser repetition rate is not synchronized to the pulse scanning optics. The pulse width of the laser is ~85ns, and the pulse energy of the 1000W average power version is 67mJ at 15KHz, so the resulting peak power is 800 Kilowatts at 15KHz. The peak power exceeds the ablation threshold of most materials. The sound comes from ablation plume breaking the speed of sound as it blasts away from the surface.

Just a thought on the dust or smoke, at the start of the video there is a brief shot of the back of the handheld unit that shows what appears to be a vacuum hose along side of probably an electrical cable to power the unit. Also after he flips the grate over he is sweeping towards himself with the laser horizontal to the bars of the grate and as he comes off of the edges of the bars you can see little puffs of dust flying toward the operator ahead of the laser. Just my observation.

I suppose they take advantage of laser speckle!!! The very same thing that is undesirable in most optoelectronic imaging applications! My theory is that the surface of oxidized metal is very rough (not smooth, with microscopic holes and higher surface area than polished metal); the focused laser beam scatters through the microscopically imperfect surface and the resulting interference of waves creates points where the intensity of light is very strong (speckle), turning the air in that spot into plasma and vaporizing everything around (including rust). This is very cool!

I forgot to mention, after the rust is removed the surface of the metal is smoother and behaves more like a mirror, therefore less speckle is produced and most laser energy is reflected away from the surface in a divergent beam (which is harmless if you are using glasses tuned for the wavelength of the laser).

They have a US distributor. It would be nice if someone could visit for a demo. I am not close enough to either office, but I would imagine someone frequently here is. I find the video and web site to be less than convincing, but the basic concept doesn’t have any obvious holes. I would expect to have seen this in some of the trade rags at some point (AWS, etc), but haven’t. Then again, I haven’t been looking for it, either.

If anyone would just search around, there has been the robotic versions of this system around in the shadows for a little while. Just seems they have made it into a handheld unit so you could use it without the robotic arm is all.

As for the naysayers of this not being real. For f**k sake, look at laser etchers and laser cutters. You are telling me you can’t calibrate a laser to remove rust? More than likely this is a real thing.

Do the research first before you let your opinions come out and post them as what you view as a fact. Just because you don’t think they are real doesn’t mean they are not real. Just means its something you have not seen before. Be humble enough to look it up on the internet.

Yes but before research is done, sceptism is a sound reaction. I wish that by default people were sceptics, then we wouldn’t have to endure all the shit and lies on the internet. (and Trump)
Today people believe everything they read in print or on the internet.

That was quick! Thanks! My theory is something along the lines of it being easy(-ish) to produce a very powerful pulse, for a very short period of time. Over a second, there’s probably not much average power. Still amazing though, love to know how they actually work. Diode-pumped, I think it said. So pumping what?

Yep, any of these systems I’ve read about are diode pumped Nd:YAG with a Q-switch. Need the Q-switch for those high peak powers. Don’t see why you couldn’t use something other than YAG but I imagine YAG trumps the others in price/efficiency/performance.

So does this thing have, in the cart, a shitload of diode lasers all pointing at a Nd:YAG crystal? You can explain Q switching if you like, I’ve read about lasers before but I go a bit cross-eyed. How many diode lasers, and how big’s the crystal, do you think? I’d really really like to see inside this thing.

So where is the residue? Does it vaporize iron oxide into a colorless gas? If one were to take a wire brush to that much rust, the table would look like a sandbox afterwards. And there is no apparent smoke or air-born dust from the process.

The coefficient of emissivity of dirty metals is around 97%, but only 3% for clean metal surfaces. Once it cleans it, the LASER should just bounce right off. Which would be good for not removing too much materiel, but bad safety wise.

Not too bad. The beam is focused at some working distance (looks like a few inches) and it’s constantly scanning, so the fluence at a few feet is probably skin safe. You’d definitely need to wear goggles, but from lack of face shields on the videos, I assume they designed the diverging beam to reduce the fluence to safe levels at some defined working distance.

There are several other videos and images of these lasers systems. The video in this article only shows the laser projector unit. There’s a large fiber optic pipe, wires and a vacuum hose connected to a unit the size of a small trailer. The vacuum hose sucks up the vapor and debris the laser blasts off the surface.

One video shows it being used to strip paint from a vehicle. One pass blasts the paint, then it has to be adjusted to get the primer coat. I assume the light wave frequency and power output must be matched to the energy absorption spectra of the coating being removed.

The cost is around a quarter million dollars for the 1KW version. A shop stripping rust, paint and other coatings would have to be doing work just about 24/7 to pay for it.

They also have a 20 watt backpack model that can be plugged in or can run for a while off an internal battery. Disappointingly, the latest version of it looks far less like a proton pack than the previous iteration.

The major advance this company has made is in using diode lasers so there are no consumables, just feed it all the electricity it needs. There have been similar systems before but they used CO2 gas lasers or other kinds of consumable lasing medium lasers which added a never ending cost. Once one of these diode laser cleaners is paid off, it’s all profit minus electricity cost.

Wavelength isn’t going to be adjusted – that’ll be fixed. Power and focus are possible to adjust, as well as repetition rate, pulse duration etc.

Other benefits to diode pumped solid state lasers too, such as improved efficiency, increased reliability. Any of these I’ve read about are Diode Pumped Nd:YAG with a Q-Switch. I’ve seen AVERAGE powers of up to 1kW advertised – who knows what the peak power is at those average power levels, but it’ll be HUGE.

Seems to me it’s a laser diode pumped YAG laser. 808nm from the diodes into the YAG crystal makes 1064nm. It’s widely used in the industry for laser marking and so on. The humming sound seems to be caused by the pulsed laser. A pulsed laser is used to finally get more optical energy compared to a CW laser.
The operator didn’t keep the head in a specific distance from the object so it’s not this classical setup of a scan head and a lens. My guess, the beam diameter is very thin (the light that comes out of the colimator) and deflected by only one mirror/scanner to get the wider working area.
This is my wild guess. Any other ideas?
I have some experience with YAG lasers, but just in low power up to 50W and never made experimentswith rusted steel.
:-) Sarah

You would not want to be around a handheld blue laser with that kind of power :P
Also, you can’t get single diodes that are as powerful, nor can you combine multiple beams without compromising beam quality.

Taking it as face value that it’s real, what would be the possible dangers of using such a device for long periods of time? Obviously you’d need eye protection, but what about the particals/gas coming from the vaporised rust?

I’d prefer controlling/monitoring a robot arm doing the job via a CCTV setup, no need to get your eyes near a laser that powerful.

Haven’t worked with laser rust removal, but I did work with laser cutting and welding – here’s my take on the safety issues.

1. The beam is being spread out through a lens. If you don’t point it directly at your face, the beam should have spread out enough that a set of goggles that block near IR should be adequate safety. You do, however, need special goggles for YAG lasers; the goggles are typically rather greenish. On a CO2 laser, you can use ordinary polycarbonate goggles.

2. I’m not surprised that he doesn’t bother with gloves. One sales demonstration with laser welding was, “Here, hold the workpiece with your bare hands while you weld it.” It barely got hot because the welding heat was so localized.

3. The fume issues are pretty well understood; it’s no different from what has affected foundry workers for centuries. You do want to use good ventilation, but if you’re dealing with iron, copper, or most everyday metals, getting too much of the fumes doesn’t seem to have any long term effects. In the short term, though, if you don’t ventilate things well, the effects are pretty annoying, ranging from a nasty taste in your mouth that will have you craving lemons to nausea and headaches depending on just how much of them you get.

Actually, depends on how deep you are into the IR. Nd:YAG lasers (Which most if not all of these cleaning lasers are) operate at 1064nm – Silicon CCDs don’t have a great response at that wavelength, if any. Throw in an IR filter and other optical losses and you get something that can’t see the light from the laser.

It’s a diode pumped Q-switched Nd:YAG laser as Sarah said above. The Q-switch rep rate is adjustable from 15KHz to 40KHz. The multimode beam delivery fiber that is attached to the hand piece allows a minimum spot size of 2mm at the focal plane. The lens arrangement is an f-Theta cylindrical setup, and the focal distance is not adjustable by the user. The Rayleigh range allows for a long working distance range. The 1KW average power version produces pulses of 67 mJ pulse energy (at 15KHz), with a pulse width of ~85ns (FWHM value).
This gives up to 800KW peak power of the pulses (at 15KHz). The peak power exceeds the ablation threshold of most materials.

The 20W and 80W versions can produce shorter pulses and higher peak powers due to the way they work. It’s a Ytterbium doped fiber pumped at 976nm. The length of the gain medium is such that Q-switching is not practical (the gain medium is so long it will self-Q switch due to the imbalance in gain depletion at one end of the fiber and population saturation at the other end). So in this case the laser operates as a linear amplifier, with the seed pulses produced by a laser diode of appropriate wavelength. The Ytterbium fiber has a gain bandwidth that covers the ~1015nm to ~1065nm band (depending on pump power and pump wavelength), so the pulsed seed diode can be anywhere in that range. The pulse width of these systems depends on the pulse width of the seed diode, so 10ns pulses can be produced pretty easily.

Which is actually not a bad price. Less than $1000 per watt of average power. Keeping in mind that cost per watt typically goes up as output power goes up too (Complexity increases with increased power).

Seriously Hackaday? I have seen this thing > 5 years ago… Youtube acutally hosts videos 7 years old. Laser cleaning has been state of the art for many years now and you behave like you found some unknown alien technology that will change the world from now on.
If you post something like that, at least go to the effort of adding patent numbers or explain how it works, so you will add any value.

It’s new to a lot of us here, and certainly interested some. “Fuck me! A laser blaster!” is still worth telling, to people who didn’t know before. For almost every subject posted here, somebody knew about it already, and today it’s your turn to be that lucky man.

Interesting. In the first video it actually looks like it isn’t removing much but rather converting the rust (brown) back to non-hydrated iron oxide (black). Only in one of the other videos on youtube with thicker layers of rust it actually blows the rust away. Probably they use the effect of rapidly expanding water vapour inside the rust, as soon as it’s heated by the laser.
I’ve seen similar lasers for cleaning stone, btw. I’m sure this is no fake.

Clean these rusty parts from oil and grease, if needed, then cook them. Yes, I mean cooking in water. After an hour or two rust is gone and parts have a black finish. Excess oxidant can be rubbed away easily.

Something rarely known is that rusting happens only up to some 70 deg Celsius. Above that temperature a different oxidant is developed and best of this is, existing rust is converted to this other oxidant, too. This is the procedure 19th century industry used to use for blueing steel parts. “Blueing”, like giving it a black, shiny finish. They’d let their brand new parts rust intentionally, then cooked them.

If you don’t believe it, try it with a few old bolts. No need for demineralised water, cooking in tap water works well.

Watch this https://www.youtube.com/watch?v=ZVrhE7WErnY video (german) by Deutsche Bundesstiftung Umwelt (German Federal Environmental Foundation)
I definitely liked the “cleaning” of the CD. This is how I like my data erased

Watch this https://www.youtube.com/watch?v=ZVrhE7WErnY video (german) by Deutsche Bundesstiftung Umwelt (German Federal Environmental Foundation)
I definitely liked the “cleaning” of the CD. This is how I like my data to be erased :)